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Virtual Raster Memory Scannable by Row or by Column

IP.com Disclosure Number: IPCOM000081798D
Original Publication Date: 1974-Aug-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Eiselen, ET: AUTHOR

Abstract

Virtual memories comprise a limited capacity, word organized, random access, high-speed memory interacting with a slow-speed bulk memory of comparably infinite capacity. An M by N array of binary coded points forming an image, for example, and stored in the bulk memory is normally oriented in the random-access memory so that word addresses are oriented along. It is desired to selectively orient the array so that it may be word addressable in the random-access memory, along either the M or N direction.

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Virtual Raster Memory Scannable by Row or by Column

Virtual memories comprise a limited capacity, word organized, random access, high-speed memory interacting with a slow-speed bulk memory of comparably infinite capacity. An M by N array of binary coded points forming an image, for example, and stored in the bulk memory is normally oriented in the random-access memory so that word addresses are oriented along. It is desired to selectively orient the array so that it may be word addressable in the random- access memory, along either the M or N direction.

More particularly, it is desired to store the array in a bulk medium and assemble it in the random-access memory, such that the memory can be selectively filled with the array in a vertical orientation in approximately the same time as that taken for filling the memory with points taken in a horizontal orientation. Where the bulk memory consists of a multitrack disk the problem is to format the array on the disk, such that the random-access memory can be filled selectively with either a vertical or horizontal orientation in a single rotation of a disk.

The solution contemplates partitioning the M by N array into topologically adjacent square arrays of m bits on a side, where M is the word size in the random-access memory and M = k(1)m and N = k(2)m, k(1) and k(2) are integers. One or more sets of k square subarrays adjacent along the M array direction are serially stored, one after another in the first track of the multiple head disk file. A second set of k(1) adjacent subarrays along the M direction contiguous to the first set are stored, for example, in the second track of a multiple head file. This process would continue until all of the square subarrays had been stored. Thus, if the points within a 4 x 4 subarray were numbered and row organized su...